ROBERT TYCHKOWSKI, QMI Agency

So that’s why the Oilers added a few more answers to the multiple-choice question of who’s playing defence on Tuesday.

Tom Gilbert missed Monday’s practice to rest the knee he banged up Sunday in Vancouver and they’re still not sure if Jim Vandermeer’s ankle will be good to go against the Sabres.

“From a medical perspective we have to make sure about some people and I won’t know about that till Tuesday morning,” said Renney. “I have a couple of guys who are a little gimpy. There are options but I don’t know what I’m going to do yet.”

If they’re both scratched it would leave Edmonton shorthanded on the blueline, so they’ve called Jeff Petry up from Oklahoma to make sure they’re covered.

“We’re on guard here, we’re bringing Jeff in to have a look at him, have him on guard at least. We’re taking that precaution.”

Petry, 23, has 21 points (7-14-21) in 32 games with the Barons. The six-foot-three 200-pounder was Edmonton’s second-round pick (45th overall) in the 2006 NHL Entry Draft.

If Gilbert doesn’t play it’ll be the first time he’s been sidelined by an injury since he joined the Oilers in 2006-07.

He played 82, 82 and 82 games the last three years (Andrew Cogliano is the only other Oiler with perfect attendance the last three seasons).

“I’m going to tell you it’s day-to-day, but we’re very cautious,” said Renney. “He has a bit of knee injury. He’s doing fine, he was doing way better today, but I’m one of those guys where, if it costs a game to play the rest of the year, I’m going to do those things.”

If Gilbert and Vandermeer are both ready, joining Ales Hemsky, who’s scheduled to return against Buffalo, then Petry would swell the ranks to 25 players, meaning they’d have to trim two bodies to get down to the 23-man limit.

That would likely mean sending Petry and another player (possibly Linus Omark). Neither Omark, nor the fans in Edmonton, would be crazy about that move.

The Oilers could also postpone the decision by placing someone on injured reserve.

“I’m looking at who’s injured and can’t play, first and foremost, that’s really where my mindset is,” said Renney. “If we have to send somebody down we’ll cross that bridge when we come to it. But I can’t speculate given where guys are in their treatment and rehab. I’m trying not to worry about (possible demotions) because it’s a tough call.”

HE SAID IT: “You don’t just step in after missing 10 and just take off. But he’s in terrific condition and he’s worked very hard. He’s anxious to go. He’s an elite player, yes, but we have to keep our expectations in place.” — Renney on Ales Hemsky’s return from a groin injury.